JPH0777167A - Pressure switch for high-pressure pump - Google Patents

Abstract

PURPOSE:To obtain an inexpensive and convenient pressure switch for a high- pressure pump by adopting an electronic circuit system which utilizes variation of current values of a high pressure regulation valve of the pump and a pump driving motor to a return valve operating pressure switch, without increasing a size of the pump device. CONSTITUTION:When a switch 30 of a power unit is turned ON, a pump driving motor 1 is operated with a charging battery 8 being a power source. Voltage is generated at both ends of a current detecting resist 31. First and second circuits 32, 39 are connected to the sides of the mobor 1. The first circuit 32 detects a current between the value of an unloaded condition of the motor 1 and the value of the maximum load condition. The detected signal is stored in a memory circuit 37. The second circuit 39 detects a current in the unloaded condition of the motor 1. etected signals of the circuits 32, 39 are input to an AND circuit 44. By the output therefrom, a return valve operating motor 4 is operated through a relay 47, and the return valve is opened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure switch for returning high-pressure hydraulic oil to an oil tank in an electric hydraulic pump used in electrical installation work, and more particularly to a novel pressure switch using an electronic circuit.

[0002]

2. Description of the Related Art Electric high-pressure pumps are used in electrical installation work such as operating actuators such as hydraulic compressors to crush crimp terminals and sleeves to connect electric wires. In such an electric high-pressure pump that has an oil tank and reciprocates a plunger by rotation of a cam shaft connected to a motor, a rechargeable battery is used as a power source, and a low flow rate of 100 to 300 cc / min on the high-pressure side. 5 with hydraulic oil
A portable rechargeable high-pressure pump capable of producing a high pressure of 0 to 100 MPa is also available.

[0003]

However, in the hydraulic pump, since the hydraulic fluid of the actuator cannot be returned only by the high pressure regulating valve, after the required work is completed, the return valve is automatically operated to return the hydraulic fluid to the oil tank. A pressure switch is required for this purpose, and as such a pressure switch, a spring type switch combining a spring and a micro switch that is distorted under hydraulic pressure, a sensor type switch combining a strain gauge, or a piezoelectric type switch is used. However, although the spring type has a relatively simple structure, when it is used for a high pressure pump close to 100 MPa, the shape and weight are large, and ultra high pressure piping is required to connect to a high hydraulic circuit. There are many mounting problems, such as the above-mentioned sensor type or piezoelectric type. Te is an expensive, there is a problem that it is unsuitable particularly for the charging high-pressure pump that oriented economic efficiency.

The present invention has been made to solve the above-mentioned problems. Even for a high-pressure pump, the shape and weight do not increase, there are few problems in mounting, and the cost is relatively low. An object of the present invention is to provide a pressure switch suitable for a small-sized rechargeable high-pressure pump powered by a portable battery.

[0005]

In order to achieve the above object, the present invention provides a high pressure regulating valve for operating a cam plunger by driving a motor to generate hydraulic pressure and for maintaining high pressure hydraulic oil at a predetermined hydraulic pressure. And a pressure switch for opening and closing the return valve in the high-pressure pump, which outputs a detection signal based on a current value that is greater than no load and less than maximum load in a loaded state of the motor, and stores the detected signal in a storage circuit. 1 circuit and a second circuit for outputting a detection signal based on a current value in a no-load state of the motor after the high pressure regulating valve is operated, and a signal output of the first circuit is provided for the second circuit. And a signal output from the AND circuit, and the output of the AND circuit operates a return valve operating motor via a relay to open the return valve. It is intended to propose a pitch.

[0006]

In this high-pressure pump, by turning on the switch and operating the motor for driving the cam plunger, the hydraulic oil in the oil tank is introduced into the hydraulic circuit to increase its pressure, and this hydraulic pressure causes the actuator such as the cylinder of the compressor to operate. Can be moved to perform pressure work. After the required pressurizing work is completed, when the hydraulic pressure in the hydraulic circuit reaches a predetermined upper limit value, the high pressure regulating valve is opened and closed to operate the hydraulic pressure to lower the hydraulic circuit to a no-load state.

When the hydraulic circuit is brought into an unloaded state by the operation of the high pressure regulating valve, the output signal stored in the first circuit of the circuit mechanism forming the pressurizing switch and the unloaded current value circuit of the second circuit are used. Are simultaneously input to the AND circuit. Then, the output signal from this AND circuit excites the relay to connect the electric circuit and operate the return valve operating motor to open the return valve, so that the hydraulic oil in the actuator is automatically transferred to the oil tank. Can be returned to.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pressure switch for a high pressure pump according to the present invention will be described below with reference to the drawings according to the embodiments. 1 is an electronic circuit diagram showing a pressure switch of the present invention, FIG. 2 is a partially cutaway side view of a rechargeable high-pressure pump provided with the pressure switch of FIG. 1, and FIG. 3 is a partially exploded side cross-sectional view of the high-pressure pump of FIG. 4 is an enlarged front cross-sectional view showing the return unit of the high-pressure pump of FIG. 2, and FIG. 5 (a) is a chart and a diagram showing the relationship between the current value and time relating to the operation of the pump driving motor of the high-pressure pump of FIG. 5 (b) is a diagram showing the relationship between the pressure of the hydraulic circuit and time by associating time with FIG. 5 (a), and FIG. 6 is a hydraulic circuit diagram of the high pressure pump of FIG.

As shown in FIG. 2, a high pressure pump A provided with a pressure switch according to the present invention has a power unit 2 provided with a pump driving motor 1, a pump block 3 connected to a lower portion of the power unit 2, and a return unit. Valve operating motor 4
And a return unit 5 attached to the upper side of the pump block 3 so that it can be carried and carried.
It is housed in Case 6.

The high-pressure pump A is provided with a battery holder 7 in the rear part thereof to detachably mount a rechargeable battery 8 of 15 to 30 A at 8.4 to 24 V, and its terminal is connected to the above-mentioned terminal via a controller (not shown). The pump driving motor 1 and the return valve operating motor 4 are cord-connected, and the controller and the metal outlet 9 attached to the front part of the case 6 are cord-connected, and an external switch is connected to the metal outlet 9. With this external switch, the pump driving motor 1 is driven to perform the pump operation, and the obtained high-pressure hydraulic oil is supplied to the actuator such as the compressor via the coupler 10.
Further, the return valve operating motor 4 is driven to return the hydraulic oil in the hydraulic circuit to the oil tank 11.

Further, description will be made with reference to FIG. The power unit 2 operates the pump driving motor 1 to rotate the cam shaft 12 at a speed reduced by the planetary gear speed reduction mechanism. The cam shaft 12 has two eccentric directions different by 180 °. The portions 12a and 12b are combined, and the upper end portions of the cam plungers 13A and 13B are attached to the cam portions 12a and 12b, respectively. That is, the upper ends of the cam plungers 13A and 13B are formed in a ring body having an oval cross section (see FIG. 4), and the cam shaft 12 is rotated by the operation of the pump driving motor 1 to form the ram chamber formed in the pump block 3. Both cam plungers 13A and 13B fitted in 14A and 14B can be alternately reciprocated to perform a pumping action.

The oil tank 11 attached to the pump block 3 is filled with hydraulic oil 15, and a filter is attached to the suction port 16 of the pump block 3 into which the hydraulic oil 15 is taken. The intake port 16 has two branched intake passages 17
A and 17B communicate with each other, and the suction passage 17A of them is
The ram chamber 14 is provided via a suction valve 18 by a spring biasing means.
In addition to communicating with A, it is possible to communicate with the high pressure passage 20 via the discharge valve 19 by the spring biasing means. The suction passage 17B communicates with the ram chamber 14B via a suction valve 21 by a spring biasing means, and further, a high pressure passage 20 via a discharge valve 22 by a spring biasing means.
I am able to communicate with. Also, this high pressure passage 20
Is communicated with the oil tank 11 via the return passage 24 via the high pressure regulating valve 23 by the spring biasing means.

The return unit 5 is a mechanism capable of forcibly returning the high pressure hydraulic oil in the high pressure passage 20 to the oil tank 11, and as shown in FIG.
Inside, the return passage 24 and the high pressure passage 20 are communicated with each other via a return valve 25 by a spring biasing means, and a push pin 26 that abuts on the return valve 25 and projects the head out of the pump block 3 is provided. It is provided. On the other hand, on the other hand, a cylinder 28 is internally provided in the return unit body 27 attached to the pump block 3, and a return unit cam 29 which can be rotated by the return valve operating motor 4 via the reduction mechanism is provided in the cylinder 28. The push pin 26 is arranged so that the head of the push pin 26 is projected into the cylinder 28 so that the push pin 26 can be intermittently pressed by the rotating return unit cam 29. That is, the push pin 26 is pushed by the drive operation of the return valve operating motor 4 by the pressure switch, which will be described later, so that the hydraulic oil in the high pressure passage 20 can be returned to the oil tank 11 via the return passage 24.

The pressure switch of the present invention comprises an electronic circuit mechanism for exciting the relay to connect the electric circuit of the return unit 5 and driving the return valve operating motor 4. When the pump driving motor 1 of the high pressure pump A is operated, the cam action of the cam plungers 13A and 13B is performed, and the hydraulic pressure of the hydraulic circuit rises. As shown in FIG. 5A, the current value in this case shows a high value of 30 to 40 A when the pump driving motor 1 is started, but immediately drops to 3 to 10 A in the no-load state b. To do.

Further, referring to FIG. 5 (b) showing the hydraulic pressure condition of the hydraulic circuit, when this pump action starts, the hydraulic pressure increases in a substantially linear manner from f to g in proportion to time. , The current value also increases substantially linearly from b to d. When the hydraulic pressure reaches 100 Mpa which is the upper limit hydraulic pressure value g set for protection of the actuator or the compressor 52 (FIG. 6) and the high pressure pump A, the high pressure regulating valve 23 operates,
When the high pressure hydraulic oil returns to the oil tank 11 and there is no load h
Then, the current value also suddenly drops from the maximum current value d of 20 to 35 A to the minimum current value e of 3 to 10 A. Then, the high pressure regulating valve 23 is automatically closed. The pressure switch of the present invention utilizes the fact that the oil pressure and the current value are in a substantially proportional relationship at the time of this oil pressure load, and that the current value rapidly drops from the maximum value d to the minimum value e due to the high pressure regulating valve. .

The pressure switch of the present invention will be described with reference to the electronic circuit diagram of FIG. When the switch 30 of the power unit 2 is turned on, the pump driving motor 1 is operated by using the rechargeable battery 8 as a power source, and the cam plungers 13A, 1
3B is driven to perform a pumping action. The current load applied to the pump driving motor 1 as the hydraulic pressure increases due to the pump action can be measured as a voltage value by the resistance 31 for detecting the current value.

That is, since a voltage is generated at both ends of the resistor 31 for detecting the current value, the first electronic circuit 32 for connecting one side of the input end to the motor side of the resistor 31 is provided. A regulator 33 is connected to the other side of the first electronic circuit 32, and an intermediate current value larger than the no-load current value and smaller than the maximum-load current value is applied to the current value detecting resistor 31 (see FIG. 5).
(Corresponding to c in (a)), the voltage generated when a current of 10 to 18 A flows is constantly generated, and the voltage value generated by the current from the circuit connected to the other end of the resistor 31 with this as a reference. Is provided with an intermediate current value detection circuit 36 including a comparator 34 and an amplifier 35 that outputs a signal when a reference intermediate voltage value is reached, and the output signal is input to a storage circuit 37 including a latch circuit. , I made it remember. The capacitor 38 attached to the storage circuit 37 absorbs the starting noise due to the high current at the time of starting the pump driving motor 1 and prevents the malfunction at the time of detecting the intermediate current value.

On the other hand, a second electronic circuit 39 for connecting one side of the input end to the motor side of the resistor 31 is provided. A regulator 40 is connected to the other side of the second electronic circuit 39 and is set so that a voltage generated when a current having a no load current value flows is constantly generated in a resistor for detecting a current value. Along with the current from the other end of 31, it can be input to the no-load current value detection circuit 41. The no-load current value detection circuit 41 includes a comparator 42 and an amplifier 43, and outputs a signal when the current passing through the current value detecting resistor 31 reaches the no-load current value.

The first electronic circuit 32 and the second electronic circuit 39
The output signal from the AND circuit is designed to be input to an AND circuit with an amplifier, that is, an AND circuit 44.
Then, the signal can be output when the intermediate current value detection signal from the first electronic circuit 32 and the no-load current value detection signal from the second electronic circuit 39 are simultaneously input. Therefore, when the current flowing through the pump driving motor 1 reaches a continuous no-load state while passing through the intermediate current region, the AND circuit 44 outputs a signal.

Further, this output signal is amplified, a current flows through the coil 45 through the transistor 45, and the relay 4
7, the switch 48 of the return unit 5 can be connected, the rechargeable battery 8 is used as a power source to operate the return valve operating motor 4, and the return valve 25 can be opened. The attached manual switch 49 is used when a preliminary cylinder returning operation of the compressor 52 is performed, for example, when the pressurizing work is redone.

The operating condition of the high-pressure pump A will be described with reference to the hydraulic circuit diagram of FIG. 6. When the switch 30 of the power unit 2 is turned on, the pump drive motor 1 is operated by using the rechargeable battery 8 as a power source to operate the cam plunger. Thirteen
A and 13B are driven, the working oil in the oil tank 11 is sucked through the suction port 16 and the suction passages 17A and 17B, and is discharged to the high pressure passage 20. The high pressure hydraulic oil in the high pressure passage 20 is transferred from the couplers 10, 50a to the pressure resistant hose 50 and the coupler 5.
It is supplied to the compressor 52 via 0b and 51.

The high-pressure regulating valve 23 is designed to open at a high pressure of 100 MPa, and a part of the high-pressure hydraulic oil is returned from the return passage 24 to the oil tank 11, whereby the inside of the high-pressure passage 20 is crushed. 50 to 1 required for isoelectric construction
It can be maintained at a high pressure of 00 MPa.

On the other hand, as shown in the electronic circuit diagram of FIG. 1, in the first electronic circuit 32 in the pressure switch, the signal output from the intermediate current value detection circuit 36 in accordance with the driving of the pump driving motor 1. Is stored in the memory circuit 37, and when the pressurizing work such as crushing in the compressor 52 is completed and the high pressure regulating valve is operated to enter the no load state, a signal is output from the no load current value detection circuit 41. In response to this signal, the output signal from the storage circuit 37 is simultaneously input, and the signal from the AND circuit 44 is output. Therefore, the output signal excites the relay 47 via the transistor 45 and the switch 48. , The electric circuit is connected, and the return valve operating motor 4 is operated by using the rechargeable battery 8 as a power source. Therefore, the return unit cam 29 of the return unit 5 rotates, pushes the push pin 26, opens the return valve 25, and the high pressure hydraulic oil in the high pressure passage 20 returns to the oil tank 11 via the return passage 24 and returns to the compressor. 5
It will return to the completely unloaded state before starting to 2.

[0024]

As described above, according to the present invention, the pressure switch for operating the return valve is different from the conventional mechanical structure in that only the high pressure regulating valve of the pump and the current value of the pump driving motor are changed. Since it uses an electronic circuit system that effectively uses the pump, it does not have to be a large-sized pump device, and there is no problem in mounting when ultra-high pressure piping is required. A highly convenient pressure switch can be obtained, and in particular, a pressure switch suitable for a portable rechargeable high-pressure pump can be obtained.

[Brief description of drawings]

FIG. 1 is an electronic circuit diagram showing a pressure switch of the present invention.

FIG. 2 is a partially cutaway side view of the rechargeable high pressure pump provided with the pressure switch of FIG.

FIG. 3 is a partially developed side sectional view of the high pressure pump of FIG.

4 is an enlarged front sectional view showing a return unit of the high-pressure pump of FIG.

5A is a chart showing the relationship between the current value and time relating to the operation of the pump driving motor of the high-pressure pump shown in FIG. 2, and FIG. 4 is a chart showing the relationship between the pressure of the hydraulic circuit and the time relating to the operation of the operating motor.

FIG. 6 is a hydraulic circuit diagram of the high-pressure pump of FIG.

[Explanation of Codes] A high-pressure pump 1 pump driving motor 2 power unit 3 pump block 4 return valve operating motor 5 return unit 6 case 7 battery holder 8 rechargeable battery 9 metal outlet 10 coupler 11 oil tank 12 camshafts 12a, 12b Cam portion 13A, 13B Cam plunger 14A, 14B Ram chamber 15 Hydraulic oil 16 Suction port 17A, 17B Suction passage 18 Suction valve 19 Discharge valve 20 High pressure passage 21 Suction valve 22 Discharge valve 23 High pressure regulation valve 24 Return passage 25 Return valve 26 Push Pin 27 Return unit body 28 Cylinder 29 Return unit cam 30 Switch 31 Resistance 32 First electronic circuit 33 Regulator 34 Comparator 35 Amplifier 36 Intermediate current value detection circuit 37 Storage circuit 38 Capacitor 39 Second electronic circuit 40 Regulator 41 No-load current value detection circuit 42 Comparator 43 Amplifier 44 Logical product circuit 45 Transistor 46 Coil 47 Relay 48 Switch 49 Manual switch 50a Coupler 50b Coupler 50 Pressure resistant hose 51 Coupler 52 Compressor

Claims (1)

[Claims] 1. A high pressure regulating valve for operating a cam plunger by driving a motor to generate hydraulic pressure and for maintaining high pressure hydraulic oil at a predetermined hydraulic pressure, and a return valve for returning the high pressure hydraulic oil to an oil tank. In a high-pressure pump, a pressure switch for opening and closing the return valve, which detects a current value that is greater than no load and less than maximum load in a loaded state of the motor, outputs a signal, and stores the signal in a storage circuit. 1 circuit, and a second circuit that detects a current value in a no-load state of the motor after the high-pressure regulating valve is activated and outputs a signal, wherein the signal output of the first circuit is the second circuit. Input to the AND circuit together with the signal output of the circuit, and the output thereof operates a return valve operating motor via a relay to open the return valve. Pressure switch for the pump.